Moore's [Profit] Law

Topological insulators are a fascinating new class of materials that feature an insulating bulk, but metallic surfaces. This means that, although it is the same material through and through (not necessarily a multi-layered heterostructure), electrons cannot travel through the interior of the material, but can easily zoom around at the material’s surfaces. Previously, physicists have only uncovered materials that are purely insulating, semiconducting, or conducting. The discovery of a class of materials that features both insulating and metallic behavior in a single system rocked the condensed matter physics community (the folks who study electrons on periodic crystal lattices), and publications with the words “topological insulator” have increased in number almost exponentially since the early 2000s, when they first started gaining attention.